xref: /freebsd/sys/fs/msdosfs/fat.h (revision 71625ec9ad2a9bc8c09784fbd23b759830e0ee5f)
1 /*	$NetBSD: fat.h,v 1.12 1997/11/17 15:36:36 ws Exp $	*/
2 
3 /*-
4  * SPDX-License-Identifier: BSD-4-Clause
5  *
6  * Copyright (C) 1994, 1997 Wolfgang Solfrank.
7  * Copyright (C) 1994, 1997 TooLs GmbH.
8  * All rights reserved.
9  * Original code by Paul Popelka (paulp@uts.amdahl.com) (see below).
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  * 3. All advertising materials mentioning features or use of this software
20  *    must display the following acknowledgement:
21  *	This product includes software developed by TooLs GmbH.
22  * 4. The name of TooLs GmbH may not be used to endorse or promote products
23  *    derived from this software without specific prior written permission.
24  *
25  * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
26  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
27  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
28  * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
29  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
30  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
31  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
32  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
33  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
34  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
35  */
36 /*-
37  * Written by Paul Popelka (paulp@uts.amdahl.com)
38  *
39  * You can do anything you want with this software, just don't say you wrote
40  * it, and don't remove this notice.
41  *
42  * This software is provided "as is".
43  *
44  * The author supplies this software to be publicly redistributed on the
45  * understanding that the author is not responsible for the correct
46  * functioning of this software in any circumstances and is not liable for
47  * any damages caused by this software.
48  *
49  * October 1992
50  */
51 
52 #ifndef _FS_MSDOSFS_FAT_H_
53 #define	_FS_MSDOSFS_FAT_H_
54 /*
55  * Some useful cluster numbers.
56  */
57 #define	MSDOSFSROOT	0		/* cluster 0 means the root dir */
58 #define	CLUST_FREE	0		/* cluster 0 also means a free cluster */
59 #define	MSDOSFSFREE	CLUST_FREE
60 #define	CLUST_FIRST	2		/* first legal cluster number */
61 #define	CLUST_RSRVD	0xfffffff6	/* reserved cluster range */
62 #define	CLUST_BAD	0xfffffff7	/* a cluster with a defect */
63 #define	CLUST_EOFS	0xfffffff8	/* start of eof cluster range */
64 #define	CLUST_EOFE	0xffffffff	/* end of eof cluster range */
65 
66 #define	FAT12_MASK	0x00000fff	/* mask for 12 bit cluster numbers */
67 #define	FAT16_MASK	0x0000ffff	/* mask for 16 bit cluster numbers */
68 #define	FAT32_MASK	0x0fffffff	/* mask for FAT32 cluster numbers */
69 
70 /*
71  * MSDOSFS:
72  * Return true if filesystem uses 12 bit FATs. Microsoft Programmer's
73  * Reference says if the maximum cluster number in a filesystem is greater
74  * than 4084 ((CLUST_RSRVD - CLUST_FIRST) & FAT12_MASK) then we've got a
75  * 16 bit FAT filesystem. While mounting, the result of this test is stored
76  * in pm_fatentrysize.
77  */
78 #define	FAT12(pmp)	(pmp->pm_fatmask == FAT12_MASK)
79 #define	FAT16(pmp)	(pmp->pm_fatmask == FAT16_MASK)
80 #define	FAT32(pmp)	(pmp->pm_fatmask == FAT32_MASK)
81 
82 #define	MSDOSFSEOF(pmp, cn)	((((cn) | ~(pmp)->pm_fatmask) & CLUST_EOFS) == CLUST_EOFS)
83 
84 #if defined (_KERNEL) || defined(MAKEFS)
85 /*
86  * These are the values for the function argument to the function
87  * fatentry().
88  */
89 #define	FAT_GET		0x0001	/* get a FAT entry */
90 #define	FAT_SET		0x0002	/* set a FAT entry */
91 #define	FAT_GET_AND_SET	(FAT_GET | FAT_SET)
92 
93 /*
94  * Flags to extendfile:
95  */
96 #define	DE_CLEAR	1	/* Zero out the blocks allocated */
97 
98 int pcbmap(struct denode *dep, u_long findcn, daddr_t *bnp, u_long *cnp, int* sp);
99 void clusterfree(struct msdosfsmount *pmp, u_long cn);
100 int clusteralloc(struct msdosfsmount *pmp, u_long start, u_long count, u_long fillwith, u_long *retcluster, u_long *got);
101 int fatentry(int function, struct msdosfsmount *pmp, u_long cluster, u_long *oldcontents, u_long newcontents);
102 int freeclusterchain(struct msdosfsmount *pmp, u_long startchain);
103 int extendfile(struct denode *dep, u_long count, struct buf **bpp, u_long *ncp, int flags);
104 void fc_purge(struct denode *dep, u_int frcn);
105 int markvoldirty_upgrade(struct msdosfsmount *pmp, bool dirty, bool rw_upgrade);
106 
107 static inline int
markvoldirty(struct msdosfsmount * pmp,bool dirty)108 markvoldirty(struct msdosfsmount *pmp, bool dirty)
109 {
110 	return (markvoldirty_upgrade(pmp, dirty, false));
111 }
112 
113 #endif	/* _KERNEL || MAKEFS */
114 #endif	/* !_FS_MSDOSFS_FAT_H_ */
115